Apparatus for making intravenous or intra-arterial injections

ABSTRACT

An apparatus for and method of making intravenous or intraarterial injections such as forced blood transfusions or the like. In a preferred embodiment of the apparatus a modular construction is provided including a first housing unit for the air pressure chamber which receives the flexible blood container or the like and subjects it to a predetermined controlled air pressure. The modular assembly may include a second housing unit for a plenum chamber in fluid communication with the pressure chamber through an air pressure regulator. A third housing unit may be provided to receive an air compressor for supplying the plenum chamber with air. The plenum chamber may also be charged either from the hospital air supply or by the compressor with sufficient air for a predetermined number of blood transfusions and used in conjunction with the air pressure regulator and pressure chamber as a portable subassembly. In another modification, the pressure chamber or a pressure cuff may be connected directly to the hospital air supply through the air pressure regulator without using a plenum chamber in the system.

llnite States [151 Dancy, Jr. [451 Feb. 1972 [54] APPARATUS FOR MAKHNG 1,869,443 8/1932 Stocklin ..l28/215 HNTRAVENOUS 0R llNTRA-ARTEHAL INJECTIONS Primary Examiner-Dalton L. Truluck Attorney-Robert C. Sullivan, Robert B. Benson and Charles [72] Inventor: Robert C. Dnncy, .llr., Brookfield, Wis. L. Schwab [73] Assignee: Allis-Chalmers Manufacturing Company Milwaukee, Wis. [57] ABSTRACT An apparatus for and method of making intravenous or intra- [22] 1970 arterial injections such as forced blood transfusions or the [21] Appl. No; 11,745 like. In a preferred embodiment of the apparatus a modular construction is provided including a first housing unit for the air pressure chamber which receives the flexible blood con- [52] "128/214 128/ tainer or the like and subjects it to a predetermined controlled air pressure. The modular assembly may include a second [51] lnt.Cl. ..A6lrn 05/00 housing unit for a plenum chamber in fluid communication [58] Field of Search ..12s/213, 214, 214.2, 215-216, with the pressure chamber through an air pressure regulator 128/225, DIG. 13; 222/94, 96, 95, 105, 61, 386.5,

399 389 A third housing unit may be provided to receive an air compressor for supplying the plenum chamber with air. The [56] Referem Cited plenum chamber may also be charged either from the hospital air supply or by the compressor with sufficient air for a UNITED STATES PATENTS predetermined number of blood transfusions and used in conunction with the air pressure regulator and pressure chamber 2,766,907 10/1956 wallacemas a portable subassembly. in another modification, the pres- 3468308 9/1969 sure chamber or a pressure cuff may be connected directly to 1,956,006 4/ 1934 Coons: the hospital air supply through the air pressure regulator 3,486,539 12/1969 Jacuzzl without using a plenum chamber in the system. 3,044,663 7/1962 Norton et al.. 3,491,377 1/ 1970 Bolie 2 Claims, 11 Drawing Figures 7? 3a, V J1 37 J 7] 06' M5 X4 if APPARATUS FOR MAKING INTRAVENOUS OR INTRA- ARTERIAL INJECTIONS BACKGROUND osrna INVENTION l. Field of the Invention This invention relates to an apparatus for and method of making intravenous or intra-arterial injections, such as blood transfusions.

2. Description of the Prior Art h In the administration of intravenous fluids such as blood to the body, it is often necessary to accelerate the flow. For example, in the administration of blood during surgery or after an accident it is often desirable to administer previously collected blood at faster rates than gravity flow'permits. For a considerable period, it has been known to employ for this purpose manually operable blood pumps which operate on the squeeze bulb principle. A disadvantage of the manually operated pumping devices heretofore utilized is that they do not provide an easily measurable uniform pumping action on the blood so that the administrator can regulate the rate at which blood is being transfused It is also known to provide positive pumping arrangements for pumping blood at controlled rates, as illustrated by U.S. Pat. No. 3,052,238-issued to C. R. Broman et al. on Sept. 4, 1962, and No. 3,425,415 issued to E. S. Gordon et al. on Feb. 4, 1969.

SUMMARY OF THE INVENTION It is an object of the invention to provide an adjustable automatic pressure regulating system for intravenous or intra-ardifferent embodiments of the invention. a

It is a further object of the invention to provide an apparatus for and method of making intravenous or intra-arterial injections or the like such as blood transfusions, for example, in which the gas or air pressure applied to the fluid being transfused may bederived from the hospital gas or air supply, which gas supply in accordance with the invention is subjected to adjustable automatic pressure regulation before being appliedto the fluid being transfused.

In describing the invention, air will be cited as the type of gas used as the pressure medium, and in most cases air would be the gas used for this purpose. However, it will be understood that other suitable gases could be used for this purpose. Also, the invention will be described as embodied in an apparatus for and method of intravenously transfusing blood or other intravenous fluids, However, it will be understood that the apparatus and method are equally applicable for use in connection with the intra-arterial injection of blood, although higher gas pressure values would be required for intra-arterial injections than for intravenous injections.

In achievement of these objectives, there is provided in accordance with this invention an apparatus for and method of making intravenous or intra-arterial injections such as forced blood transfusions. In a preferred embodiment of the apparatus a modular construction is provided including a first housing unit for the air pressure chamber which receives the flexible blood container or the like and subjects it to a predetermined controlled air pressure. The modular assembly may include a second housing unit for a plenum chamber in fluid communication with the pressure chamber through an air pressure regulator. A third housing unit may be provided to BRIEF DESCRIPTION OF THEDRAWINGS FIG. 1 is an operational schematic diagram of a forced blood transfusion system in accordance with the invention;

FIG. 2 is an external perspective view of a modular apparatus for use with the system of FIG. 1;

FIG. 3 is another external view from a different angle of the modular apparatus of FIG. I, and showing the cover member of the pressure chamber partially open;

FIG. 4 is a view in longitudinal section of the apparatus of FIGS. 2 and 3; n

FIG. 5 is a fragmentary view in longitudinal section of the modular apparatus of FIGS. 2-4, inclusive, showing details of the latching and interlock mechanism associated with the cover member of the pressure chamber;

FIG. 6 is a fragmentary view showing details of the quick detachable connection of the pressure regulator and of the filter to the wall of the pressure chamber of the modular apparatus of FIGS. 2-5, inclusive; 1

FIG. 7 is a schematic operational diagram of a modified embodiment of the invention;

FIG. 8 is a detail view of the inlet fitting to the pressure chamber which may beconnected to aflexible conduit leading to the plenum chamber or which may alternatively be connected to a flexible conduit leading to a manually operated ball pump which may be used to manually supply pressure to the pressure chamber;

FIG. 9 is a detail view of a'blowout seal which may he used to prevent excessive pressure in the pressure chamber and in the plenum chamber;

FIG. 10 is a front elevation view of a pressure cuff which may be used to apply pressure to the flexible blood container or the like; and

FIG. 11 isa view in transverse section along line XI-XI of FIG. 10 showing the flexible blood container being supported by the pressure cuff.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1 which shows an operational schematic for a forced blood transfusion system in accordance with the invention, there is shown a conduit generally indicated at 10 including an inlet end 12 which may be connected to a compressor generally indicated at 16 which may form part of the modular apparatus to be described hereinafter.

As will be described in more detail later and as seen schematically in FIG. 1, air from compressor 16 passes into accumulator or plenum 18 which serves as a reservoir or storage chamber for air which passes through filter 24, regulator 26 and on-off valve 30 to pressure chamber 32.

Instead of using compressor 16 as a source of air supply, and as seen schematically in FIG. 1, the hospital air supply generally indicated at 1 4 in FIG. I may be used as an air supply. The hospital air supply may be connected directly to the input of the filter-regulator subassembly 24-26 as at 25A from whence the air passes through on-off valve 3 to the pressure chamber 32. In this case, accumulator or plenum chamber 18 is disconnected from the system. Alternatively, the hospital air supply 14 may be connected to inlet 12 as at 12A to charge up accumulator or plenum chamber 18 with sufficient air to service a plurality of blood transfusion units, such as 12 units, for example. After the plenum chamber I8 has been charged as just described, it is disconnected from the air supply and the combination of the charged plenum chamber 18 and the pressure chamber 32 may be used as a portable subassembly for administering a plurality of intravenous injections.

The accumulator generally indicated at 18 which may be embodied as the plenum chamber to be described hereinafter as part of the modular apparatus, is connected in fluid communication with conduit a short distance downstream of inlet connection 12, accumulator 18 being connected to conduit 10 by means of a tubular connection 19. A pressure indicator 20 is connected in fluid communication with the interior of accumulator 18 whereby to indicate the fluid pressure internally of accumulator 18. A blowout seal 22 is provided in the wall of accumulator 18 to permit pressure relief at a predetermined pressure internally of the accumulator. A filter 24 is connected in series fluid communication with con duit 10 downstream of accumulator 18 whereby to filter out any impurities in the air or other fluid being conducted through conduit 10 before the air reaches the regulator. An automatic pressure regulator generally indicated at 26 is connected in series with conduit 10 downstream of filter 24. The pressure regulator is capable of regulating the input air pressure thereto to provide a predetermine output air pressure at the outlet end of the regulator, and the value of outlet pressure to be maintained by the regulator may be adjusted by means of adjusting knob 28 to provide a desired value of output pressure. Despite any fluctuations in input gas pressure from the source of supply, regulator 26 maintains a constant output pressure, assuming that a sufficient pressure differential is maintained across the regulator to satisfy the dynamic requirements of regulation, as is well known in the art of gas pressure regulation. For example, the regulator may maintain an output pressure within a range of O to 500 millimeters of mercury with an air flow rate in the range of 2 to 20 milliliters per second.

The pressure regulator 26 may be of any suitable commercially available type and, for example, may be a Fairchild- Hiller part catalog 10122, model 10 precision regulator.

This air pressure regulator is a product of Fairchild-Hiller Industrial Products Division, 1501 Fairchild Drive, Smith Reynolds Airport, Winston-Salem, NC. 27105, and is described in a Fairchild-Hiller bulletin identified as W.P. Co. 8876467." Another air pressure regulator which may be used is Regulator No. 3R06-l00-RNE produced by Beckett- Harcum Co., 985 West Locust St., PO. Box 809, Wilmington, Ohio 45 l 77, and described in Beckctt-Harcum Catalog ALC, printed .lan., I968.

The output fitting of regulator 26 is connected to conduit 10, and an on-ofl' valve 30 is connected in series with the portion of conduit 10 extending from the outlet end of regulator 26 to the inlet end of the pressure chamber generally indicated at 32 in which the blood container 38 is received. The regulator 26 should be of the bleeding type. This may be accomplished by providing an air leakage or bleeding hole in the regulator 26 or in the conduit portion 10C upstream of on-off valve 30. This permits the output pressure maintained by the regulator to be adjusted from a given output pressure value to a lower value. Valve 30 should be moved to closed position when the pressure setting to be maintained by the regulator is being readjusted to a different value by rotation of control knob 28. As will be explained later, on-off valve 30 is suitably interlocked with movable cover member 34 of the pressure chamber 32 in such manner that when cover member 34 is moved to open position, valve 30 is automatically moved to closed position, whereby to interrupt the fluid connection between regulator 26 and pressure chamber 32. A suitable pressure indicator 36 is interposed in conduit 10 between the regulator 26 and on-off valve 30 to provide a reading of the injection pressure in pressure chamber 32, and to indicate the preset pressure existing in conduit 10C when on-off valve 30 is in the closed position.

A flexible or pliable blood container 38 in the form of a sterile plastic bag or the like containing 500 milliliters of blood (the standard unit)is positioned in pressure chamber 32 and is subjected to the air pressure inside chamber 32. A flexible conduit 40 having a hypodermic needle termination is inserted through a rubber or plastic plug in blood container 38. The flexible conduit 40 connected to blood container 38 passes through a suitable sealed aperture in the wall of chamber 32 and is connected to a suitable drip device 42 used in administering blood or other intravenous liquid material to the patient.

Referring now to FIGS. 2-5, inclusive, there is shown a modular construction which may be utilized to house the various components of the system of FIG. 1. Thus, in FIGS. 2-5 inclusive, there is shown a modular assembly generally indicated at 50 comprising an integrated interlocked assembly of three housing units of generally polyhedral shape including a compressor housing unit 16', a plenum chamber housing unit 18', and a pressure chamber housing unit 32. Each of the housing units 16', 18' and 32 has the same shape in horizontal cross section and is of the same peripheral shape to permit vertical stacking of the intermediate or plenum chamber housing unit 18 on top of the compressor housing unit 16' and to permit stacking of the pressure chamber housing unit 32' on top of the intermediate housing unit 18', as best seen in the views of FIGS. 2 and 3.

As best seen in the view of FIG. 4, the upper edges of the four sidewalls of the compressor housing unit 16 are rabbeted as indicated at 52, and the interfitting lower portions of the four sidewalls 54 of the plenum housing unit 18 are so dimensioned as to be received in interfitting relation to the rabbeted portions 52 of the compressor housing unit 16'. In a similar manner, the upper edges of the four sidewalls of the plenum housing unit 18 are rabbeted as indicated at 56, and the corresponding lower edges of the sidewalls 58 of the pressure chamber housing unit 32 are dimensioned to properly interfit with the rabbeted edges of the plenum housing unit 18'. It will be understood, of course, that the bottom, top, and sidewalls of the plenum chamber housing unit 18 enclose the plenum chamber 18; and that similarly the bottom, top and sidewalls of the pressure chamber housing unit 32' enclose the pressure chamber 32. The bottom walls of plenum chamber housing unit 18 and of pressure chamber housing unit 32' are spaced above the lower ends of the sidewalls of the respective housing units 18' and 32'.

As best seen in the view of FIG. 4, the compressor housing unit 16 is provided with a suitable fluid outlet fitting 60 which is suitably connected to the output of the compressor 16 contained within compressor housing unit 16'. The plenum chamber housing section 18 is provided with a suitable fluid inlet fitting 62. When he compressor is being used to supply air to plenum chamber 18, a suitable flexible conduit 64 is connected between fluid outlet fitting 60 of compressor housing unit 16' and fluid inlet fitting 62 of plenum housing unit 18. Fluid inlet fitting 62 includes a check valve 63 which permits fluid flow into plenum chamber 18 but prevents reverse flow therefrom. In a similar manner, plenum housing unit 18 is provided with a fluid outlet fitting 66 and pressure chamber 32 is provided with a suitable fluid inlet fitting 68. Outlet fitting 66 of chamber 18 incorporates a suitable manually operated shutoff valve 67 which can be moved to closed position when required. When plenum chamber 18 is being used as a source of air supply for pressure chamber 32 as shown in the operational schematic system of FIG. 1, and as shown in the assembled views of FIGS. 2, 3 and 4, fluid outlet fitting 66 of plenum chamber 18 is connected by flexible conduit 10A to the inlet fitting 25 leading to filter 24, the output offilter 24, in turn, being connected by flexible conduit 10B to the input of air pressure regulator 26. Inlet fitting 25 includes a check valve 29 which permits fluid flow into filter 24 moving toward regulator 26 and pressure chamber 32, but prevents fluid flow in the reverse direction. The output of regulator 26 is connected by flexible conduit 10C to the input side of on-off valve 30 which is mounted on forward wall 32A of pressure chamber housing unit 32' (FIG. 2). Conduit section 10D connects the output side of valve 30 to the input fitting 68 of pressure chamber 32. Input fitting 68 of chamber 32 incorporates a check valve 73 which prevents reverse flow of gas from pressure chamber 32. The position of valve 30 is controlled by the interlock arrangement with cover 34 of pressure chamber 32 as will be described in more detail hereinafter.

As best seen in the view of FIG. 6, regulator 26 may be detachably connected by a clip connection or the like to the inside surface of one of the sidewalls of pressure chamber housing unit 32' below bottom wall 37 of the pressure chamber 32. Filter 24 may be detachably connected in the same manner as the regulator. This permits easy attachment and detachment of regulator 26 and filter 24 when desired, thereby facilitating maintenance of the filter and the regulator. Suitable access means (not shown) may be provided in the various housing sections for making the necessary conduit and component connections.

As seen in FIGS. 2 and 5, the combination cover latching and interlock arrangement for valve 30 is mounted on the front wall 32'A of pressure chamber housing unit 32. Cover or closure member 34 of the pressure chamber is pivotally connected at one end at 70 for pivotal movement about a normally horizontal axis, and is provided at its opposite end with a cover detent member 72 which is rigidly fixed to and movable with cover 34. Detent member 72 includes a rearwardly extending portion 74 which is adapted to cooperate with a latching mechanism generally indicated at 76 supported by front wall 32A of pressure chamber housing unit 32. A pair of laterally spaced bearing bracket numbers 78 are mounted on the forward surface of wall 32 A of pressure chamber housing unit 32'. A shaft 80 is supported for rotary angular movement by laterally spaced bearing brackets 78. On-off valve 30 is connected to or forms a part of one end of shaft 80 in such manner that rotation of shaft 80 is effective to move valve 30 from its on" to its off position or vice versa depending upon the direction of rotation of shaft 80. An operating handle 82 is connected to shaft 80 whereby rotation of handle 82 is effective to impart a rotary angular movement to shaft 80. A flexible latching member 83 formed of spring steel or the like has one of its ends fixed to shaft 80 as indicated at 84 and a portion of the length of flexible latching member 83 in the closed or latched position of cover 34 is wound around a portion of the periphery of shaft 80 as best seen in the view of FIG. 5. Flexible member 83 includes a tongue portion 83' which overlies portion 74 of detent member 72 in the position of the members as seen in FIG. 5. As shaft 80 is moved in a clockwise direction with respect to the view in FIG. 5 toward an unlatched position of the mechanism, a portion of the length of flexible connector 83 is payed out and rolls off of the periphery of shaft 80. A guide or cam slot 86 is provided in a corresponding portion of each of the oppositely disposed brackets 78, and a pair of oppositely extending pintles 88 are carried by flexible latching member 83 intermediate the length thereof and are received in and guided by cam slots 86 in brackets 78. Each cam slot 86 is inclined vertically upwardly to the right toward the forward wall 32A of pressure chamber housing unit 32. Thus, in moving upwardly in slots 86, pintles 88 also move to the right with respect to the view of FIG. 5.

In the position of the members as shown in FIG. 5, cover 34 is closed and the latching mechanism is in a position in which a portion of the length of flexible latching member 83 is wound about shaft 80. To open cover member 34, shaft 80 is rotated by means of handle 82 in a clockwise direction with respect to the view of FIG. 5 to cause flexible latching member 83 to move upwardly as it initially unwinds from shaft 80. During the initial portion of the movement of flexible latching member 83, member 83 and tongue portion 83' thereof move in a substantially vertical direction with tongue portion 83' still being in overlying relation to rearwardly extending por tion 74, whereby the force of the contained air pressure exerted on cover 34 causes the cover to move upwardly for a short distance without being fully released, but sufficiently to release the air pressure within pressure chamber 32.

The initial rotary movement just described of shaft in an opening direction is also effective to move on'off valve 30 to a position in which the valve is in an off position to prevent fluid communication between the accumulator or plenum chamber 18 and regulator 26 on the one hand, and the interior of pressure chamber 32 on the other hand. Thus, in the same initial movement which permits cover 34 to be moved to a venting position, valve 30 is moved to a closed position. The interlock arrangement just described between cover 34 and on-off valve 30 automatically isolates pressure chamber 32 from the air supply line 10C from regulator 26 when changing to a new unit 38 of blood.

Further rotation of shaft 80 in a clockwise direction, with respect to the view shown in FIG. 5, beyond the initial move ment just described causes the cam or guide tracks 86 to con strain flexible latching member 82 to move sufficiently to the right with respect to the view shown in FIG. 5 whereby to move tongue portion 83 of member 83 out of overlying relation to rearwardly extending portion 74 of cover latch member 72. This movement of tongue portion 83' out of the path of latch portion 74 as just described permits cover 34 of pressure chamber 32 to be manually lifted to a completely open position to permit replacement of blood container 38, if desired.

Thus, it will be seen that the latching assembly for cover 34 not only has its movement interlocked with on-off valve 30 to insure that valve 30 is moved to a closed position in the initial opening movement of the cover, but also cover 34 is movable to an open position in two distinct steps, namely, a first step in which latch member 83 is moved to a position which permits cover 34 to be manually moved to a venting position but in which tongue portion 83' of latch member 83 is still in overlying relation to portion 74 of latch member 72; and a second step or position in which latch portion 83' is moved out of overlying relation to latch portion 74 and in which cover 34 can then be manually moved to a completely open position.

As best seen in the views of FIGS. 2 and 3, the pressure gauge 20 which indicates the pressure in plenum chamber 18 is mounted on the forward wall 18'A of plenum chamber housing unit 18'. Pressure gauge 36 which measures the pressure in conduit section 10C leading to pressure chamber 32 is mounted on a sidewall of pressure chamber housing unit 32'.

Adjusting knob 28 for adjusting air pressure regulator 26 to regulate or maintain the desired pressure in pressure chamber 32 is mounted on or projects through an opening in a wall of the pressure chamber housing unit 32. Blowout seal 35 of pressure chamber 32 is mounted in a sidewall of the pressure chamber housing unit 32'; and blowout seal 22 of plenum chamber 18 is mounted in a sidewall of plenum chamber housing unit 18.

When the three housing units 16', 18 and 32' are assembled together in stacked relation as seen in the views of FIGS. 2, 3 and 4, they may be secured together by means of conventional snap locks generally indicated at 90, each snap lock 90 including cooperating elements upon the contiguous housing units which are to be assembled together. For example, the snap lock between the plenum chamber housing unit 18' and thepressure chamber housing unit 32' includes cooperating lock eleme ts on these two housing units. Snap locks 90 should be provided on opposite sides of the assembly as, for example, the left-hand side and the right-hand side surfaces as viewed in FIG. 4 of the drawings.

It should be noted that each of the housing units l6, l8 and 32' is free standing if desired and these housing units may be used in various arrangements as will now be described.

If the air compressor unit (including compressor I6 and the electric drive motor 17 therefor) contained in housing unit 16 is to be used to supply the air pressure to the system, the three housing units 16', 18 and 32 are assembled in stacked relation as shown in FIGS. 2, 3 and 4, and the plug-in cord 92 connected to the electric motor 17 driving the compressor is plugged into a source of electrical power. A suitable switch, not shown, may be provided in the circuit of the electric motor for the compressor. With the compressor unit operating, air pressure is supplied from the compressor to plenum chamber 18, the air passing from chamber 18 through filter 24, regulator 26, and on-off valve 30 to pressure chamber 32. Regulator 26 maintains the inlet air pressure to pressure chamber 32 at the value to which regulator 26 is set by adjustment of knob 28, regardless of any fluctuations in the air pressure of the supply source, assuming that sufficient pressure differential is maintained across the regulator to satisfy the dynamic requirements of regulation, as is well known in the art.

If it is desired instead of using the compressor unit to use the hospital air supply 14 (FIG. 1) as a source of air for the system, the compressor housing unit 16' and the plenum chamber housing unit 18 are detached from the assembly, and the hospital air supply 14 is directly connected to inlet fitting 25 of the filter-regulator subassembly 2426 from whence the air passes through filter 24, regulator 26 and onoff valve 30 as previously described to pressure chamber 32, the hospital air being regulated by regulator 26 to provide a constant air pressure in pressure chamber 32.

Still another manner in which the apparatus of the invention may be employed, using an assembly of units 18' and 32', and using either the compressor 16 as an air supply or alternatively using the hospital air supply, is to fill plenum chamber 18 with a sufficient amount of air to supply the necessary air pressure for a plurality of blood transfusions as, for example, 12 transfusions of a standard 500 milliliter blood container unit 38. With plenum chamber 18 charged with a sufficient volume of air as just explained, the plenum chamber housing unit 18' and the pressure chamber housing unit 32' may be used in assembled relation with each other as a portable subassembly, the compressor housing unit 16 being detached from and not forming part of the subassembly. The filled plenum chamber 18 will supply air through filter 24, regulator 26 and on-off valve 30 to inlet fitting 68 of pressure chamber 32 in the same manner previously described. Since in this arrangement plenum chamber 18 is filled with sufficient air for a number of successive transfusion units, the portable assembly of housing units 18' and 32' may be carried about the hospital and used for transfusions as a self-contained subassembly wherever needed, as long as sufficient stored air remains in plenum chamber 18. Each time a blood container unit is placed in the pressure chamber the chamber must be refilled with air to the required pressure. Also, as each container is being drained of blood, a volume of air equal to the volume of blood removed from the container must flow into the pressure chamber.

A still further possible manner of using the apparatus is in conjunction with a conventional ball air pump which is manually operated and which is directly connected by a flexible conduit to inlet fitting 68 of pressure chamber 32. When the manually operated ball air pump is used, the compressor housing unit 16 and the plenum chamber housing unit 18' may be detached from the assembly shown in FIGS. 2, 3 and 4, with only the pressure chamber housing unit 32' being used.

When the ball air pump is used as just described, the flexible conduit conventionally provided with the ball air pump has the end thereof screwed onto the screw-threaded portion 69 of the inlet fitting 68 to the pressure chamber 32 (FIG. 8), so that the air from the ball air pump passes directly into the pressure chamber 32, and does not pass through the air filter 24, the pressure regulator 26 and the on-off valve 30. It will be noted that fitting 68 is also provided with angular pronglike elements 71 which are adapted to grip the flexible end of the conduit 10D used when housing unit 32 is assembled with plenum chamber housing unit 18 in the other assembly arrangements described.

As seen in FIG. 9, blowout seal 22 is a threaded caplike member adapted to be received in a screw-threaded aperture in the wall of the plenum chamber housing unit 18'. The blowout seal comprises a blowout membrane 23 which is adapted to fracture or break at a predetermined internal pressure in plenum chamber 18. A protective screen 27 is provided at the outer end of blowout seal 22 to protect membrane 23 against external damage. Blowout membrane 23 should be designed to fracture when the internal pressure in plenum chamber 18 exceeds a predetermined value based on the design strength of plenum chamber housing unit 18'. Blowout seal 35 of pressure chamber 32 is similar to blowout seal 22 just described, although the blowout membrane of seal 35 is designed to fracture at a difierent pressure than the membrane of blowout seal 22.

Referring now to FIG. 7, there is shown an operational schematic diagram of a modified forced blood transfusion system which is connected to the hospital air supply 100. The inlet air from the hospital air supply may have a pressure in the range of 20 to 250 p.s.i. The conduit connecting the hospital air supply to the transfusion unit generally indicated at 102 is generally indicated at 104. Conduit 104 is provided with a male coupling which is keyed to fit into only a standard female socket for air. This is a standard coupling used in all operating rooms to prevent inadvertent connection to oxygen which might lead to an explosion. The hospital air supply 100 is electrically grounded. Conduit 104 is preferably plastic tubing impregnated with a conducting material to pass any electrical static charges to ground. This is standard tubing used in all operating room equipment to prevent electrical discharges which potentially might cause an explosion. The modular system of FIGS. 16 should also be grounded and all tubing thereof should be electrically conductive to pass static charges to ground. A metering orifice 106 is provided in conduit section 104 between air supply 100 and pressure regulator 108. Metering orifice 106 acts in conjunction with the relief valve to be described to prevent rupture of the rubber or elastomeric bag forming the pressure cuff of the transfusion unit to be described, in case of failure of pressure regulator 108. The pressure at which rupture of the pressure cuff would occur as just described is approximately 700 mm. of mercury.

Downstream of metering orifice 106 is the air pressure regulator generally indicated at 108 which is connected in series fluid flow relation with conduit 104. Air pressure regulator may be of any suitable type such as those previously described in the previous embodiment of the invention and may, for example, be a Fairchild-Hiller catalog 10122, Model l0 precision regulator, or a Beckett-Harcum Regulator No. 3RO6-l OO-RNE. Regulator 108 is provided with an adjusting knob 110 which may be manually adjusted to regulate the cuff pressure of the transfusion unit within a range of 0-425 mm. of mercury with an air flow rate of approximately 2-20 milliliters per second. Regulator 108 should be a bleeding regulator as previously described. A pressure gauge 112 is connected in conduit 104 downstream of pressure regulator 108 and should be capable of reading a pressure in the range of O600 mm. of mercury. A relief valve 114 is connected in the conduit 104 downstream of pressure gauge 112 and should be designed to operate at an appropriate value such as 500 mm. of mercury to relieve an over pressure condition in the system in the event of functional failure of pressure regulator 108.

A two-way valve 116 is connected in conduit 104 downstream of relief valve 114 and has two positions. In one position of two-way valve 116 the air flow in conduit 104 is in fluid communication with the pressure cuff 118 of the transfusion unit, while in the other position of two-way valve 116 the connection of the air supply source 100 to pressure cuff 118 is closed and instead the conduit section 1048 between the twoway valve 116 and the pressure cuff 118 is vented to atmosphere through the two-way valve, thus venting the interior of pressure cufi 118 to atmosphere. The two-way valve is moved to venting position, for example, when a new blood container 122 is being positioned in the pressure cuff.

As best seen in FIGS. 7, 10 and 11, the blood transfusion unit generally indicated at 102 includes the pressure cuff 118 which may be a closed baglike member formed of rubber or other elastomeric material. The pressure cuff has a hollow interior which is connected to air supply conduit 104 by conduit section 104B. An upwardly open pocketlike portion 120 formed of nylon netting material or the like is suitably affixed to one of the major surfaces of pressure cuff 118, pocket portion 120 serving as a receptacle for the flexible blood container 122. Outlet tube 124 of blood container 122 passes through an opening 126 provided at the lower portion of pocket 120, tube 124 thence passing into the-blood dispensing unit 128, FIG. 7. The controlled air pressure inside pressure cuff 118 exerts a pressure against the flexible blood container 122 which is held in close contact with the surface of the pressure cuff by pocket portion 120. The pressure inside pressure cuff 118 is maintained at an adjusted constant pressure by pressure regulator 108. The pressure exerted by the pressure cuff on the flexible blood container 122 causes the blood to be discharged into the patient at a constant flow rate. The pressure at which the blood flows into the patient is nearly that indicated by the pressure gauge 112 in FIG. 7. Since the flow and venous pressure is low, regulating the injection pressure is equivalent to transfusing blood at a constant flow rate.

In the system of FIG. 7, the pressure chamber 32 of the embodiments of FIGS. 2, 3 and 4 may be substituted in place of the pressure cuff 118 of FIG. 7, in which case the outlet end of conduit section 104B of FIG. 7 would be connected directly to inlet fitting 68 of the pressure chamber housing unit 32'. Also, in the system of FIG. 7, a compressor could be substituted for the hospital air supply as the source of air for the system. However, since no plenum chamber is used in the system schematically shown in FIG. 7, a compressor of larger flow rate capacity is required than would be required if a plenum chamber were being used.

It can be seen that in accordance with the invention there is provided a system and apparatus for providing intravenous or intra-arterial injections such as blood transfusions or the like in which the injection may be made under a controlled air or gas pressure which can be preset and which is maintained at a constant predetermined desired value regardless of fluctuations in the source pressure by an air pressure regulator in the system, the controlled air pressure forcing the liquid such as blood from the dispensing unit into the patient at a constant rate. Furthermore, there is provided in accordance with the invention an integrated system of modular components which permit a great degree of flexibility in their arrangement and operation. Thus, using the pressure chamber alone, the system can be operated manually with a ball air pump or can be operated by the regulating system of FIGS. 1 and 7. The pressure chamber portion of the apparatus used alone can also be used as a gravity feed device for the blood or the like being injected. When the pressure chamber 32 is used in conjunction with the regulator it can be operated either using the plenum chamber 18 supplied by the compressor or it can be operated directly on hospital air subject to regulation by the regulating device and without the plenum chamber.

Still a further arrangement in accordance with which the apparatus may be used is that the plenum chamber may be charged up with air by either the compressor or by the hospital air supply to a pressure and volume sufficient for a predetermined number of transfusions, such as twelve 500-milliliter transfusions. With the air thus stored in the plenum chamber, the assembly of the pressure chamber and the plenum chamber may be used as a portable assembly and taken wherever required for use in making intravenous injections such as blood transfusions.

A compressor of low flow rate capability can be used with the plenum for use in administering intravenous or intra-arterial injections assuming the plenum is initially charged with air. In this case, the compressor only has to furnish air as the blood is displaced from the blood container and to recharge the pressure chamber after it has been opened to remove and replace a blood unit.

From the foregoing detailed description of the present invention, it has been shown how the objects of the invention have been obtained in a preferred manner. However, modifications and equivalents of the disclosed concepts such as readily occur to those skilled in the art are intended to be included within the scope of this invention.

The embodiments of the invention in WhICh an exclusive property or privilege is claimed are defined as follows:

1 An apparatus for use in administering intravenous or intra-arterial liquid injections comprising a pressure chamber, a flexible or pliable container which holds the liquid to be in- 20 jected, said container being positioned in said pressure chamber, means extending fromsaid container to the exterior of said pressure chamber for connecting said container in transfusing relation to a patient, a gas supply, conduit means connecting said gas supply to said pressure chamber, gas pressure regulating means interposed in said conduit means for regulating the pressure of gas admitted to said pressure chamber, said pressure chamber including a closure member movable to an open position to permit access to the interior of said pressure chamber, said conduit means being provided with an on-off valve which in off position interrupts fluid communication between said gas supply and said pressure chamber, and means interlocking said valve with said closure member whereby said valve is moved to said off position upon movement of said closure member to open position.

2. An apparatus for use in administering intravenous or intra-arterial liquid injections comprising a pressure chamber housing unit having a pressure chamber therein, a flexible or pliable container which holds the liquid to be injected, said container being positioned in said pressure chamber, means extending from said container to the exterior of said pressure chamber for connecting said container in transfusing relation to a patient, a plenum chamber housing unit, said plenum chamber housing unit containing a plenum chamber for storing gas to be admitted to said pressure chamber, said plenum chamber being adapted to be connected to a source of gas supply, said pressure chamber housing unit and said plenum chamber housing unit being engageable with each other in a modular assembly, conduit means connecting said plenum chamber to said pressure chamber, gas pressure regulating means interposed in said conduit means for regulating the pressure of gas admitted to said pressure chamber, said pressure chamber housing unit including a closure member movable to an open position to permit access to the interior of said pressure chamber, said conduit means being provided with an on-off valve which in off position interrupts fluid communication between said plenum chamber and said pressure chamber, and means interlocking said valve with said closure member whereby said valve is moved to said off position upon movement of said closure member to open position. 

1. An apparatus for use in administering intravenous or intraarterial liquid injections comprising a pressure chamber, a flexible or pliable container which holds the liquid to be injected, said container being positioned in said pressure chamber, means extending from said container to the exterior of said pressure chamber for connecting said container in transfusing relation to a patient, a gas supply, conduit means connecting said gas supply to said pressure chamber, gas pressure regulating means interposed in said conduit means for regulating the pressure of gas admitted to said pressure chamber, said pressure chamber including a closure member movable to an open position to permit access to the interior of said pressure chamber, said conduit means being provided with an on-off valve which in off position interrupts fluid communication between said gas supply and said pressure chamber, and means interlocking said valve with said closure member whereby said valve is moved to said off position upon movement of said closure member to open position.
 2. An apparatus for use in administering intravenous or intra-arterial liquid injections comprising a pressure chamber housing unit having a pressure chamber therein, a flexible or pliable container which holds the liquid to be injected, said container being positioned in said pressure chamber, means extending from said container to the exterior of said pressure chamber for connecting said container in transfusing relation to a patient, a plenum chamber housing unit, said plenum chamber housing unit containing a plenum chamber for storing gas to be admitted to said pressure chamber, said plenum chamber being adapted to be connected to a source of gas supply, said pressure chamber housing unit and said plenum chamber housing unit being engageable with each other in a modular assembly, conduit means connecting said plenum chamber to said pressure chamber, gas pressure regulating means interposed in said conduit means for regulating the pressure of gas admitted to said pressure chamber, said pressure chamber housing unit including a closure member movable to an open position to permit access to the interior of said pressure chamber, said conduit means being provided with an on-off valve which in off position interrupts fluid communication between said plenum chamber and said pressure chamber, and means interlocking said valve with said closure member whereby said valve is moved to said off position upon movement of said closure member to open position. 